Question

The length of a social media interaction is normally distributed with a mean of 3 minutes and a standard deviation of 0.4 minutes.

What is the probability that an interaction lasts longer than 4 minutes?


1)0.0045254
2)0.043351
3)0.0095254
4)0.006209

Answer 1

Your answer is the last one.

Answer 2

Answer: 4) 0.0062097

Explanation:

Given : The length of a social media interaction is normally distributed with a mean of
`\mu=3` minutes and a standard deviation of
`\sigma=0` minutes.

Using the formula ,
`z=(x-\mu)/(\sigma)`, the z-value corresponding to x=4 will be :-

`z=(4-3)/(0.4)=2.5`

Using the standard normal distribution table for z-value , the probability that an interaction lasts longer than 4 minutes will be :-

`P(z>2.5)=1-P(z\leq2.5)=1-0.9937903=0.0062097`

Hence, the probability that an interaction lasts longer than 4 minutes = 0.0062097